Alloy



' should contain all Patented Dec. 28,1926.

UITED STATES PATENT OFFICE.

EARL H. RICHARDSON, 0F QN'I'AEIO, CALIFORNIA,

ASSIGNdR TO EDISON ELECTRIC APPLIANCE G'DMPANY, INC.. A CORPORATION OF NEW YORK.

ALLOY, I

lt'o Drawing. original application tiled February 21, 1921, Berle 1 application filed August 11, 19:32. Serial No.

My invention relates'tq alloys, particularly to fusible alloys such as used for the protection of electrical devices, and has for its object the provision of an improved alloy of this character.

My improved alloy is particularly ap l1- cable for use as a protective device in e ectric flat irons, such, for example, as described and claimed in my co ending application, Serial No. 446,618, led February 21, 1921, now Patent No. 1,439,979, of whic this application is a division.

Considerable difiic ulty has been experienced in providing a fusible alloy that is not affected by oxidation upon repeated melting and solidifying. It is also desirable that the alloyhave a quick break down from the solid to the liquid state, that is, the alloy should change froma solid toa liquid without going through an intermediate granular or mushy condition. Ice upon melting gives a very good example of this characteristic, the change to a liquid taking place without any noticeable intermediate condition.

In carrying out my invention I have provided an alloy composed approximately of 90% zinc, 4% bismuth and 6% aluminum. These proportions are not necessarily absolute but should be adhered to within rea-- sonable limits. in order to obtainthe best results the metals should'be as nearly ure as possible. The metals are mixed whi e in a molten state.

l have found that for best results the mixture of zinc, bismuth and aluminum the bismuth that it will absorb. The proportions given above may result in a slight excess of bismuth, whereby the condition of saturation with bismuth 1S assured. Any such excess, which may contain small quantities of zinc and aluminum, settles to the bottom of the crucible while the mixture is in the li uid form, and upon solidifying is separate by a rather distinct line of demarcation with respect to the remaining portion of the mixture. The excess can be easily removed from the cast ingot by a sharp blow with a hammer, and can be used in th preparation of another batch of alloy.

This alloy has the desirable features previously mentioned in that it is to ,a large degree non-oxidizable, and the transition from a solid to a liquid takes place quickly in. 448,618. Divided and um 581,242.

and without going through a granular or mushy condition to any: considerable extent. The melting point of this alloy is a proximately 750 degrees F. and is practice ly constant in the transition from the solid to the liquid state and vice versa. A change in the proportions of the metals. given does not materially affect the melting'point until the change assumes considerable magnitude.

I have thus provided an alloy the characteristics of which are not affected to any great extent by repeated melting and solidifying. Its action in operating the control mechanism with which it' may be associated is quick and definite when the melting temperature is reached, due to its quick break down. This latter feature is of especial advantage when using the allo for securing a control member embedded't herein and for releasing the member when a redetermined temperature 'isreached. uch control mechanism to which my alloy may be applied is disclosed in my aforesaid copending application.

While I have described a specific 'embodiment of 'my invention in accordance with the revisions of the patent statutes, it shou d be understood that I do not limit my invention thereto, since various modifica-' tions thereof will suggest themselves to. those skilled in the art without departing from the spirit of my invention, the scopefof which is set forth in theannexed claims.

at I claim as new and desire't'o secure by Letters Patent of the United States, 1s:-

1. A fusible alloy consistingpredominantly of zinc, the remainder consisting principally of aluminum and bismuth inquantities sufiicient to lend their properties to the alloy. v

2. A fusible alloy consisting principally, of azinc base and substantial amounts but less than 10% each, of bismuth and alummum.

3. A fusible alloy consisting predominantly of zinc, the remainder consisting principally of at least 5% of aluminum, and approximately 4% of bismuth.

4. A fusible alloy containing approximately per cent zinc, 4 per cent bismuth and 6 per cent aluminum.

5. A fusible alloy having a melting point of approximately 750 F. consisting princinpntiy of mine, the mmmmfler semis-"ding 7. A fusible alloy having a quick breakdawn consisting preiominantly of zinc, the remainder consisting principally of small 10 amounts of aluminum and bismuth.

in fi'itBQSS whereof, I have hereunto set my hand this first day of August, 1922.

EARL Y. RICHARDfiUN. 

